San Diego  The well-documented delays for northbound crossers at the San Ysidro Port of Entry don’t only involve economic costs, says a new report. For those who contend with lengthy waits amid fumes from cars and buses, there is also a significant health risk.

Possible ways to achieve that, it says, include increased staffing, greater use of technology and enrollment in pre-screening programs such as Sentri. Federal authorities would not disagree with these measures, and say that completing the expansion of the San Ysidro border crossing is also critical to reducing the waits — but Congress has yet to approve funding to complete the project, whose total cost is now estimated at $732 million.

“Exposure to traffic is not good for you, and that’s completely avoidable,” said Penelope Quintana, who teaches public health at San Diego State University and is one of the authors of the report, which compiles data from academic and government sources.

“The people who are bearing the brunt of these exposures are affected by decisions made in other places such as Washington.”

Other recommended measures include creating buffer zones to minimize the effect of border traffic on pedestrians and nearby communities, measuring exposures at all U.S.-Mexico border crossings, and identifying the types of vehicles that emit the most pollution at border crossings.

The report cites research by doctoral candidate Vanessa E. Galaviz showing that pedestrians who wait in line to cross absorb carcinogens found in diesel exhaust at seven times the level of those who live and work in the nearby San Ysidro community but did not wait in line.

Studies show that exposure to traffic emissions can lead to a range of ailments, including respiratory problems, cardiovascular effects, cancer, adverse birth outcomes and increased risk for diabetes.

While a handful of studies look at the health effects of border waits on the Canadian border, there are none for the 1,969-mile U.S.-Mexico border, with its 43 ports of entry. The report gathers existing air quality data relevant to the region, coordinated by scholars from San Diego State University and Mexican researchers at Tijuana’s Colegio de la Frontera Norte and the Autonomous University of Baja California.

While San Diego County’s Air Pollution Control District and the U.S. Environmental Protection Agency monitor air quality near the border, “we’ve never had specific information about air quality at ports entry,” said Paul Ganster, director of the Institute for Regional Studies of the Californias, and former chair of an independent federal advisory committee called the Good Neighbor Environmental Board.

“Communities and public policy people need to be thinking about what we can do to minimize the high exposures that people experience at border crossings,” Ganster said.

One recent study had drivers go from the Tijuana campus of the Autonomous University of Baja California to San Diego State University, crossing at San Ysidro in vehicles equipped with GPS systems to determine their location, and instruments to measure traffic-related pollutants such as ultrafine particles.

“We found that not only were the levels very high as they’re waiting in line, it contributed to the majority of exposure for their trip,” Quintana said.

The concern about air pollution at U.S.-Mexico border crossings has grown as wait times at San Ysidro and other land ports of entry have risen along with increased security measures following the Sept. 11, 2001 terrorist attacks. During peak weekend traffic periods, delays can be three and four hours both for cars and pedestrian crossers at San Ysidro.

“There is a preventable public health disaster that needs to be resolved,” said Paula Stigler, one of the authors, a PhD candidate in global health at SDSU and UC San Diego. “It is is critical to develop sustainable solutions to this enormous problem.”